A Doping Bits Based BP Decoding for Rateless Distributed Source Coding Applications

A novel doping bits based belief propagation decoding algorithm, for rate-adaptive LDPC codes based on fixed bipartite graph code, is proposed. The proposed work modifies the decoding algorithm, by converting the puncturing nodes to regular source nodes and by following the encoding rule at the decoder. The transmitted doping bits in place of punctured bits, with the modified decoding algorithm at the decoder, feed all the punctured nodes with reliable log likelihood ratios. This enables the proposed decoding algorithm to recover all punctured nodes in the early iteration. The fast convergence leads to decoder complexity reduction while providing considerable improvement in performance.